Attested profusely in Classical Chinese, this word is the prototypical negation particle in the *m- series of Chinese negatives. In the oracle bone script, however, 無 is not frequently used, and its homophone (or near-homophone) 毋 (OC *ma) is used instead.

See 不 (OC *pɯ, *pɯʔ, *pɯ', “not”) for more on negative particles in Old Chinese.